#32 Fix of NPE in pursuit game

core/src/cz/nic/tablexia/util/listener/DragAndRotateActorListener.java

@@ -121,7 +121,9 @@ public class DragAndRotateActorListener extends InputListener {
                 if (activePointers.size() == 0) {
                     //if user removed all fingers before animation finished, piece is stopped and animated back to its original position
                     if (!isPieceAnimationDone()) {
-                        pieceTranslationAction.interrupt();
+                        if (pieceTranslationAction != null) {
+                            pieceTranslationAction.interrupt();
+                        }
                         Point pieceOriginalPosition = ((Grid) parentActor).getPieceGridPositionInPixels(((PuzzlePiece) draggedActor).getActualPosition());
                         parentActor.addAction(new RotateAndMovePieceInPosition((PuzzlePiece) draggedActor, actorOriginalRotation, pieceOriginalPosition, iOnRotationFinished));
                     }